1. Field of the Invention
The invention relates to a sensor device, having at least one optical sensor, a container and a compartmentalization means.
2. Description of the Related Art
In medical technology and biotechnology, optical sensors are used, in particular, in disposable reactors, mixing reactors and bioreactors or in disposable containers, mixing containers and biocontainers. In these and similar fields of application it is often necessary to sterilize a container before use. Sterilization by means of radiation, more particularly gamma radiation, has proven its worth in the field of disposable products; however, this radiation is damaging to optical sensors. This particularly affects optical sensors based on porous matrices, such as, for example, fluorescence-based pH sensors. Thus an effective protection system, which can simultaneously be implemented in a cost-effective fashion, is required for such sensors.
WO 02/056023 A1 and DE 100 51 220 A1 have disclosed optical sensors for measuring at least one parameter in a sample. These sensors are based on a device for exciting fluorescence in an analyte-sensitive fluorescent dye, immobilized in a matrix in a sample vessel or reactor, which dye is at least in indirect contact with the sample, and on an evaluation device for the resulting fluorescence response signal. In this case, the analyte concentration can be evaluated or determined by utilizing both the fluorescence decay time and the fluorescence intensity. A disadvantage is the fact that such pH sensor patches, which are based on a hydrophilic carrier matrix, such as e.g. impregnated paper or sol-gel matrices, are damaged, dose-dependent, during radiation sterilization. There is a reduction in both the intensity of the fluorescence of the dye or dyes and also the sensitivity of the sensor patch with respect to the measurement variable.
U.S. Pat. No. 7,390,462 B2 has disclosed a sensor, in which the fluorescent dye is present immobilized in a hydrophilic matrix. In this case, a sensor is claimed with the pH-sensitive fluorescent dye MA-HPDS present in a hydrogel. Here too a disadvantage lies in the fact that such hydrophilic optical sensors are damaged, dose-dependent, during sterilization using gamma radiation. In laboratory technology in particular, such radiation is applied in the case of containers made of polymers. There is a reduction in both the intensity of the fluorescence of the dye or dyes and also the sensitivity of the sensor with respect to the measurement variable. There is particularly severe damage to such a sensor patch if it is in contact with a relatively large volume of air or else with conventional protective gasses such as e.g. nitrogen or argon during the radiation sterilization. The gasses are partly ionized or free radicals are created during the radiation sterilization. During, for example, the sterilization of a gas-filled polymer bag, these radicals react on the walls or else on the sensor surfaces. Sensors based on porous, hydrophilic matrices are particularly susceptible to this because the sensor chemicals must be present immobilized on the surface or inner surface of the matrix due to operating principles so that the sample to be measured can come into contact with the sensor chemicals. The extent of the damage is dependent on, firstly, the radiation dose and, secondly, the ratio of the surface to the volume of the irradiated container containing the sensor patch. This ratio determines the number of ions or radicals that damage the sensor patch or the sensor chemicals contained therein.
DE 10 2009 003 971.6 A1 has disclosed an optical sensor for measuring at least one parameter, which sensor is coated porously with a noble metal layer; this brings about a reaction of reactive particles on the noble metal layer. However, a disadvantage of this is the fact that such a coating is complicated from a technical and mechanical point of view and is connected with high costs; this is something that should be avoided, particularly in the field of disposable products.
The present invention is therefore based on the object of developing a sensor device for an optical sensor, which reduces the sensitivity of the optical sensor towards radiation, more particularly gamma radiation, and which can be implemented in a cost-effective and simple fashion.